Golf Interior Light: Replacement & Installation

Why is the interior light in the door of the Golf 4 much dimmer when it's in the "door-on" position compared to when I select the "always on" position? This is the same for both doors. There's a diode built into the wiring leading to the door contact switch in the door lock – what function does that serve? The Golf doesn't have original central locking or power windows, so it also lacks any door control modules.

You already explained it yourself.
A diode has a voltage drop in the forward direction, which is why the light appears dimmer.

My presumed reason:
The diodes allow you to distinguish between the doors.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Oh yeah, maybe I should just try closing the circuit without the diode and see what happens? There's not much else in there anyway.

RedR32 wrote:

Oh yeah, maybe I should just try closing the loop without the diode, let's see what happens? There's not much else in there anyway.

Try it out. But usually, diodes are installed for a reason, to prevent short circuits or unwanted side currents.
Depending on what purpose it serves for you, it could lead to a short circuit until the cable catches fire .

Then I'd rather just let it be and not talk about it anymore.

The diodes are included in case a comfort control module (alarm system) or interior light delay feature is installed. If neither of these features is present, the diodes are usually unnecessary.

Since VW largely manufactures the entire wiring harness itself, they keep the diodes in place despite the additional cost.
Sometimes, it's more expensive to modify the wiring harness to accommodate the "minority option" regarding how parts are installed. In those cases, the option is simply left as is.

Quote:

The Golf doesn't have original power locks or window lifters, and therefore also lacks door control modules.

Door control units are not responsible for this function; instead, the Comfort Control Unit handles it: electric front heating, electric panoramic roof (or glass roof), power-adjustable side mirrors, and power-adjustable seats.

Ach ja das KomfortSTG ist ja dafür zuständig, stimmt ja. Sitzt ja wenn vorhanden hinterm Lichtschalter überm Relaisträger. Hab ich nicht, nur eine NachrüstZV mit FB. Die TürSTG sind am Fensterhebermotor mit befestigt und steuern die Fensterheber. Hab iMe neither.
I have the bel.MakeUp vanity mirror and lighting above the B-pillar, but no alarm system or delayed interior lights.
So, would it be worth trying to remove the diodes and bridge them instead?
Just this awful weather...

Hello everyone!

@Red
Here's the translation:

"Tip: Use a fast-acting 3.15A fuse, solder two wires to it, and use it to bypass each diode individually. Then, test all possible door open/close scenarios: with/without ignition, with/without headlights, etc. ...and if it survives, the wiring harness probably will too."
Here, the main concern would be regarding the responsible state government, because a diode like that could always fail (i.e., break and become permanently conductive), and even Volkswagen, as a car manufacturer, can't afford a cable fire.

Best regards from Munich!

I rewired it today. It's working great.